anticipator settings

jaybee

Hello again everyone, I have a question about setting the heat antcipator at the proper setting. As u all know im a newbi,but i was taught in school that your settings are as follows: When u detrmine the amp draw of the primary control or controls u multiply the current draw multiplier times the amp draw of the control. In order to have proper cycleling it is recomended to as following:
Gravity Systems-(1 cycle per hr. current draw multiplier 2.00)
FWH & High EFF-(3 cycles per hr. " " " 1.4)
Warm air-(6 cycles per hr. " " " 1.0)
Electric Heat-(9 cycles per hr. " " " .7)
Is this correct? the old timers on my job tells me that this is all a "crock" and to forget all that stuff i read.They say u simply look on the control and set the anticpator to what ever is on that control.

Ken_8

U need to find some new friends.

There are two kinds of anticipators. Fixed (that are set based on time) and resistive (that are based on amp draw).

"Fixed ones" are typically on programmable stats that are digital and generally solid state. The cycle rate (times the boiler/furnace can come on in one hour) is the basis of most settings. A dip switch, circuit screw, or jumper wire is typically incorporated to make the cycle rate (ON cycles per hour) setting appropriate for the type of heating system in place. That way, one model stat with adjustable timing - can be sold to F/H/A guys, steam heads and HWBB wet-heads.

Generally, non-programmable analog type 'stats have an adjustable resister/heater inside that fakes out a bi-metal spring, and can be set to match the load attached thereto - making the cycle rate variable. It just so happens that all manufacturers of this type of stat know time has little bearing on tempature swings and have allowed the resistive internal coil to function purely on temperature - not time.

The classic example of this form of stat is Honeywell's "round" T87. That's the one that looks like a gold yo-yo stuck on the wall.

The Honeywell installation manual suggests that by setting the wiper blade on the coil/resister to the actual amp draw of the turn on the heat switch/circuit - that very accurate temps can be maintained. The trick to finding the starting point for this excercise is typically done by using an amp meter sensitive in the half-amp range.

Amp meters in the higher ranges can also be used but some wound jaw tricks are required and this answer is already too long (:-o)

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Unknown

Jaybee, what you were

told is correct. For those thermostats with adjustable anticipators those multipliers are correct. The 1.4 multiplier is the most important one when you are looking at mid and high efficiency systems.

For conventional (older) forced warm air and forced hot water set the anticipator to match the primary control that is multiply by 1.

The 1.4 was determined by Honeywell research related to high bills on mid and high efficiency equipment cycling 6 times per hour at 50% of heating load. By multiplying times 1.4 it will cause you to move up scale and decrease the number of cycles per hour (longer cycles). Example if the primary control draws .4 multiply times 1.4 will give you .56. Set to .56 is less resistance, less false heat longer cycles, less cycles.

Big Ed

Guess Work

I would think 1 cycle per-hour is too long for a gravity hot water , maybe for steam.. Steam you need a long cycle to fill the system. A steam only thermostat has the antisipator jumped out. Steam could also use other controls to set it's cycle. Like using a heat timer. Any large mass hot water system you want to nurge up in a shorter cycle as to not over ride or over heat...

I find most techs set the antisipator from what they read off the control . They are taking for granted it's marked correct, the control is perfect and there is nothing else drawing on the circuit. What they are doing is guessing .... Sure it could be on the money but how do you know? You want to take a reading and also wait a min or so, the reading could drop. Take a R117 or even some of the older zonevalves. On start up they will draw more amps until the clapper drops out or the valve locks open.The lower reading is the running amp draw .This is where you want to set or start from. Which would be 6 cycles per hour.....

GEO_3

Trouble with using numbers on the control is sometimes you have to add the gas valve and the module together and with some makes it's included. Best to use a meter so your wiring loss is included and leace the meter on till you have ignition. I find setting the amp at the highest point observed in this way works just fine.

John@Reliable_9

Jaybee, are you doing mostly oil? ..........

Check at your supply house for a amp meter that is just what your looking for. It's about 3x3 and comes w/ attached leads/clips. Very simple to use . *One hint if you run into allot of Taco zone valves like we do, set T87 @ 1.2 (high as it goes) for best setting.

John@Reliable_9

Ken, I like the yo-yo line!

Honeywell's "round" T87. That's the one that looks like a gold yo-yo stuck on the wall. P.S. you can no longer get them, now they only come in off white.